HD 43691 is a star with an orbiting exoplanet in the constellation Auriga. With an apparent visual magnitude of 8.03,^[2] it is too faint to be visible to the naked eye. This system is located at a distance of 279 light years based on parallax measurements, but is drifting closer with a heliocentric radial velocity of −29 km/s.^[2]

This is a slightly evolved G-type subgiant star with a stellar classification of G0 IV.^[3] It is ceasing thermonuclear fusion of hydrogen in its core and will expand to become a red giant. The star has 32% greater mass than the Sun and has a 70% larger girth.^[4] It is radiating 2.2 times the luminosity of the Sun from its photosphere at an effective temperature of 5,920 K.^[5] The level of chromospheric activity is minimal, allowing for accurate measurement of radial velocity variation.^[3]

In July 2007, the star is found to have a super-jovian exoplanet in orbit around it.^[3] It has minimum mass two and a half times that of Jupiter and orbits the star closer than Mercury to the Sun.

• List of extrasolar planets